// Copyright 2014 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "src/deoptimizer.h"
#include "src/macro-assembler.h"
#include "src/register-configuration.h"
#include "src/safepoint-table.h"

namespace v8 {
namespace internal {

#define __ masm->

    // This code tries to be close to ia32 code so that any changes can be
    // easily ported.
    void Deoptimizer::GenerateDeoptimizationEntries(MacroAssembler* masm,
        Isolate* isolate,
        DeoptimizeKind deopt_kind)
    {
        NoRootArrayScope no_root_array(masm);

        // Save all the registers onto the stack
        const int kNumberOfRegisters = Register::kNumRegisters;

        RegList restored_regs = kJSCallerSaved | kCalleeSaved;

        const int kDoubleRegsSize = kDoubleSize * DoubleRegister::kNumRegisters;
        const int kFloatRegsSize = kFloatSize * FloatRegister::kNumRegisters;

        // Save all double registers before messing with them.
        __ lay(sp, MemOperand(sp, -kDoubleRegsSize));
        const RegisterConfiguration* config = RegisterConfiguration::Default();
        for (int i = 0; i < config->num_allocatable_double_registers(); ++i) {
            int code = config->GetAllocatableDoubleCode(i);
            const DoubleRegister dreg = DoubleRegister::from_code(code);
            int offset = code * kDoubleSize;
            __ StoreDouble(dreg, MemOperand(sp, offset));
        }
        // Save all float registers before messing with them.
        __ lay(sp, MemOperand(sp, -kFloatRegsSize));
        for (int i = 0; i < config->num_allocatable_float_registers(); ++i) {
            int code = config->GetAllocatableFloatCode(i);
            const FloatRegister dreg = FloatRegister::from_code(code);
            int offset = code * kFloatSize;
            __ StoreFloat32(dreg, MemOperand(sp, offset));
        }

        // Push all GPRs onto the stack
        __ lay(sp, MemOperand(sp, -kNumberOfRegisters * kPointerSize));
        __ StoreMultipleP(r0, sp, MemOperand(sp)); // Save all 16 registers

        __ mov(r1, Operand(ExternalReference::Create(IsolateAddressId::kCEntryFPAddress, isolate)));
        __ StoreP(fp, MemOperand(r1));

        const int kSavedRegistersAreaSize = (kNumberOfRegisters * kPointerSize) + kDoubleRegsSize + kFloatRegsSize;

        // The bailout id is passed using r10
        __ LoadRR(r4, r10);

        // Cleanse the Return address for 31-bit
        __ CleanseP(r14);

        // Get the address of the location in the code object (r5)(return
        // address for lazy deoptimization) and compute the fp-to-sp delta in
        // register r6.
        __ LoadRR(r5, r14);

        __ la(r6, MemOperand(sp, kSavedRegistersAreaSize));
        __ SubP(r6, fp, r6);

        // Allocate a new deoptimizer object.
        // Pass six arguments in r2 to r7.
        __ PrepareCallCFunction(6, r7);
        __ LoadImmP(r2, Operand::Zero());
        Label context_check;
        __ LoadP(r3, MemOperand(fp, CommonFrameConstants::kContextOrFrameTypeOffset));
        __ JumpIfSmi(r3, &context_check);
        __ LoadP(r2, MemOperand(fp, JavaScriptFrameConstants::kFunctionOffset));
        __ bind(&context_check);
        __ LoadImmP(r3, Operand(static_cast<int>(deopt_kind)));
        // r4: bailout id already loaded.
        // r5: code address or 0 already loaded.
        // r6: Fp-to-sp delta.
        // Parm6: isolate is passed on the stack.
        __ mov(r7, Operand(ExternalReference::isolate_address(isolate)));
        __ StoreP(r7, MemOperand(sp, kStackFrameExtraParamSlot * kPointerSize));

        // Call Deoptimizer::New().
        {
            AllowExternalCallThatCantCauseGC scope(masm);
            __ CallCFunction(ExternalReference::new_deoptimizer_function(), 6);
        }

        // Preserve "deoptimizer" object in register r2 and get the input
        // frame descriptor pointer to r3 (deoptimizer->input_);
        __ LoadP(r3, MemOperand(r2, Deoptimizer::input_offset()));

        // Copy core registers into FrameDescription::registers_[kNumRegisters].
        // DCHECK_EQ(Register::kNumRegisters, kNumberOfRegisters);
        // __ mvc(MemOperand(r3, FrameDescription::registers_offset()),
        //        MemOperand(sp), kNumberOfRegisters * kPointerSize);
        // Copy core registers into FrameDescription::registers_[kNumRegisters].
        // TODO(john.yan): optimize the following code by using mvc instruction
        DCHECK_EQ(Register::kNumRegisters, kNumberOfRegisters);
        for (int i = 0; i < kNumberOfRegisters; i++) {
            int offset = (i * kPointerSize) + FrameDescription::registers_offset();
            __ LoadP(r4, MemOperand(sp, i * kPointerSize));
            __ StoreP(r4, MemOperand(r3, offset));
        }

        int double_regs_offset = FrameDescription::double_registers_offset();
        // Copy double registers to
        // double_registers_[DoubleRegister::kNumRegisters]
        for (int i = 0; i < config->num_allocatable_double_registers(); ++i) {
            int code = config->GetAllocatableDoubleCode(i);
            int dst_offset = code * kDoubleSize + double_regs_offset;
            int src_offset = code * kDoubleSize + kNumberOfRegisters * kPointerSize + kFloatRegsSize;
            // TODO(joransiu): MVC opportunity
            __ LoadDouble(d0, MemOperand(sp, src_offset));
            __ StoreDouble(d0, MemOperand(r3, dst_offset));
        }

        int float_regs_offset = FrameDescription::float_registers_offset();
        // Copy float registers to
        // float_registers_[FloatRegister::kNumRegisters]
        for (int i = 0; i < config->num_allocatable_float_registers(); ++i) {
            int code = config->GetAllocatableFloatCode(i);
            int dst_offset = code * kFloatSize + float_regs_offset;
            int src_offset = code * kFloatSize + kNumberOfRegisters * kPointerSize;
            // TODO(joransiu): MVC opportunity
            __ LoadFloat32(d0, MemOperand(sp, src_offset));
            __ StoreFloat32(d0, MemOperand(r3, dst_offset));
        }

        // Remove the saved registers from the stack.
        __ la(sp, MemOperand(sp, kSavedRegistersAreaSize));

        // Compute a pointer to the unwinding limit in register r4; that is
        // the first stack slot not part of the input frame.
        __ LoadP(r4, MemOperand(r3, FrameDescription::frame_size_offset()));
        __ AddP(r4, sp);

        // Unwind the stack down to - but not including - the unwinding
        // limit and copy the contents of the activation frame to the input
        // frame description.
        __ la(r5, MemOperand(r3, FrameDescription::frame_content_offset()));
        Label pop_loop;
        Label pop_loop_header;
        __ b(&pop_loop_header, Label::kNear);
        __ bind(&pop_loop);
        __ pop(r6);
        __ StoreP(r6, MemOperand(r5, 0));
        __ la(r5, MemOperand(r5, kPointerSize));
        __ bind(&pop_loop_header);
        __ CmpP(r4, sp);
        __ bne(&pop_loop);

        // Compute the output frame in the deoptimizer.
        __ push(r2); // Preserve deoptimizer object across call.
        // r2: deoptimizer object; r3: scratch.
        __ PrepareCallCFunction(1, r3);
        // Call Deoptimizer::ComputeOutputFrames().
        {
            AllowExternalCallThatCantCauseGC scope(masm);
            __ CallCFunction(ExternalReference::compute_output_frames_function(), 1);
        }
        __ pop(r2); // Restore deoptimizer object (class Deoptimizer).

        __ LoadP(sp, MemOperand(r2, Deoptimizer::caller_frame_top_offset()));

        // Replace the current (input) frame with the output frames.
        Label outer_push_loop, inner_push_loop, outer_loop_header, inner_loop_header;
        // Outer loop state: r6 = current "FrameDescription** output_",
        // r3 = one past the last FrameDescription**.
        __ LoadlW(r3, MemOperand(r2, Deoptimizer::output_count_offset()));
        __ LoadP(r6, MemOperand(r2, Deoptimizer::output_offset())); // r6 is output_.
        __ ShiftLeftP(r3, r3, Operand(kPointerSizeLog2));
        __ AddP(r3, r6, r3);
        __ b(&outer_loop_header, Label::kNear);

        __ bind(&outer_push_loop);
        // Inner loop state: r4 = current FrameDescription*, r5 = loop index.
        __ LoadP(r4, MemOperand(r6, 0)); // output_[ix]
        __ LoadP(r5, MemOperand(r4, FrameDescription::frame_size_offset()));
        __ b(&inner_loop_header, Label::kNear);

        __ bind(&inner_push_loop);
        __ SubP(r5, Operand(sizeof(intptr_t)));
        __ AddP(r8, r4, r5);
        __ LoadP(r8, MemOperand(r8, FrameDescription::frame_content_offset()));
        __ push(r8);

        __ bind(&inner_loop_header);
        __ CmpP(r5, Operand::Zero());
        __ bne(&inner_push_loop); // test for gt?

        __ AddP(r6, r6, Operand(kPointerSize));
        __ bind(&outer_loop_header);
        __ CmpP(r6, r3);
        __ blt(&outer_push_loop);

        __ LoadP(r3, MemOperand(r2, Deoptimizer::input_offset()));
        for (int i = 0; i < config->num_allocatable_double_registers(); ++i) {
            int code = config->GetAllocatableDoubleCode(i);
            const DoubleRegister dreg = DoubleRegister::from_code(code);
            int src_offset = code * kDoubleSize + double_regs_offset;
            __ ld(dreg, MemOperand(r3, src_offset));
        }

        // Push pc and continuation from the last output frame.
        __ LoadP(r8, MemOperand(r4, FrameDescription::pc_offset()));
        __ push(r8);
        __ LoadP(r8, MemOperand(r4, FrameDescription::continuation_offset()));
        __ push(r8);

        // Restore the registers from the last output frame.
        __ LoadRR(r1, r4);
        for (int i = kNumberOfRegisters - 1; i > 0; i--) {
            int offset = (i * kPointerSize) + FrameDescription::registers_offset();
            if ((restored_regs & (1 << i)) != 0) {
                __ LoadP(ToRegister(i), MemOperand(r1, offset));
            }
        }

        __ pop(ip); // get continuation, leave pc on stack
        __ pop(r14);
        __ Jump(ip);
        __ stop("Unreachable.");
    }

    bool Deoptimizer::PadTopOfStackRegister() { return false; }

    void FrameDescription::SetCallerPc(unsigned offset, intptr_t value)
    {
        SetFrameSlot(offset, value);
    }

    void FrameDescription::SetCallerFp(unsigned offset, intptr_t value)
    {
        SetFrameSlot(offset, value);
    }

    void FrameDescription::SetCallerConstantPool(unsigned offset, intptr_t value)
    {
        // No out-of-line constant pool support.
        UNREACHABLE();
    }

#undef __

} // namespace internal
} // namespace v8
